Monday, July 21, 2014

Common gene variants account for most genetic risk for autism

The bulk of risk, or liability, for autism spectrum disorders was traced to inherited variations in the genetic code shared by many people. 

These and other (unaccounted) factors dwarfed contributions from rare inherited, non-additive and spontaneous (de novo) genetic factors 

Credit: Population-Based Autism Genetics and Environment Study

Most of the genetic risk for autism comes from versions of genes that are common in the population rather than from rare variants or spontaneous glitches, researchers funded by the National Institutes of Health (NIH) have found.

Heritability also outweighed other risk factors in this largest study of its kind to date. About 52 percent of the risk for autism was traced to common and rare inherited variation, with spontaneous mutations contributing a modest 2.6 percent of the total risk.

"Genetic variation likely accounts for roughly 60 percent of the liability for autism, with common variants comprising the bulk of its genetic architecture," explained Joseph Buxbaum, Ph.D., of the Icahn School of Medicine at Mount Sinai (ISMMS), New York City.

"Although each exerts just a tiny effect individually, these common variations in the genetic code add up to substantial impact, taken together."

Buxbaum, and colleagues of the Population-Based Autism Genetics and Environment Study (PAGES) Consortium, report on their findings in a unique Swedish sample in the journal Nature Genetics, July 20, 2014.

"Thanks to the boost in statistical power that comes with ample sample size, autism geneticists can now detect common as well as rare genetic variation associated with risk," said Thomas R. Insel, M.D., director of the NIH's National Institute of Mental Health (NIMH).

"Knowing the nature of the genetic risk will reveal clues to the molecular roots of the disorder. Common variation may be more important than we thought."

Although autism is thought to be caused by an interplay of genetic and other factors, including environmental, consensus on their relative contributions and the outlines of its genetic architecture has remained elusive.

Recently, evidence has been mounting that genomes of people with autism are prone to harboring rare mutations, often spontaneous, that exert strong effects and can largely account for particular cases of disease.

More challenging is to gauge the collective impact on autism risk of numerous variations in the genetic code shared by most people, which are individually much subtler in effect.

Limitations of sample size and composition made it difficult to detect these effects and to estimate the relative influence of such common, rare inherited, and rare spontaneous variation.

Differences in methods and statistical models also resulted in sometimes wildly discrepant estimates of autism's heritability, ranging from 17 to 50 percent.

Meanwhile, recent genome-wide studies of schizophrenia have achieved large enough sample sizes to reveal involvement of well over 100 common gene variants in that disorder.

These promise improved understanding of the underlying biology, and even development of risk-scores, which could help predict who might benefit from early interventions to nip psychotic episodes in the bud.

With their new study, autism genetics is beginning to catch up, say the researchers. It was made possible by Sweden's universal health registry, which allowed investigators to compare a very large sample of about 3,000 people with autism with matched controls.

Researchers also brought to bear new statistical methods that allowed them to more reliably sort out the heritability of the disorder.

In addition, they were able to compare their results with a parallel study in 1.6 million Swedish families, which took into account data from twins and cousins, and factors like age of the father at birth and parents' psychiatric history.

A best-fit statistical model took form, based mostly on combined effects of multiple genes and non-shared environmental factors.

"This is a different kind of analysis than employed in previous studies," explained Thomas Lehner, Ph.D., chief of NIMH's Genomics Research Branch.

"Data from genome-wide association studies was used to identify a genetic model instead of focusing just on pinpointing genetic risk factors. The researchers were able to pick from all of the cases of illness within a population-based registry."

Now that the genetic architecture is better understood, the researchers are identifying specific genetic risk factors detected in the sample, such as deletions and duplications of genetic material and spontaneous mutations.

Even though such rare spontaneous mutations accounted for only a small fraction of autism risk, the potentially large effects of these glitches makes them important clues to understanding the molecular underpinnings of the disorder, say the researchers.

"Within a given family, the mutations could be a critical determinant that leads to the manifestation of ASD in a particular family member," said Buxbaum.

"The family may have common variation that puts it at risk, but if there is also a de novo [spontaneous} mutation on top of that, it could push an individual over the edge."

"So for many families, the interplay between common and spontaneous genetic factors could be the underlying genetic architecture of the disorder."

More information: Gaughler T, Klei L, Sanders SJ, Bodea CA, Goldberg AP, Lee AB, Mahajan M, Manaa D, Pawitan Y, Reichert J, Ripke S, Sandin S, Sklar P, Svantesson O, Reichenberg A, Hultman CH, Devlin B, Roeder K, Buxbaum JD. Most genetic risk for autism resides with common variation. Nature Genetics, July 20, 2014. dx.doi.org/10.1038/ng.3039

Tuesday, June 17, 2014

MRI technique may help prevent ADHD misdiagnosis

This shows subgroup averages of parametric maps of MRI brain iron indices: magnetic field correlation (MFC: top row) and relaxation rates R2 (second row), R2*(third row), and R2' (bottom row). 

Parametric maps, masked for regions of interests (green): caudate nucleus (CN), putamen (PUT), globus pallidus (GP) and thalamus (THL), are shown for controls (n = 27), medication-naïve ADHD patients (ADHD-non-medicated; n = 12) and ADHD patients with a history of psychostimulant treatment (ADHD-medicated; n = 10). 

The ADHD-non-medicated subgroup displayed significantly reduced striatal (CN, PUT) and thalamic MFC compared to both controls and the ADHD-medicated subgroup. 

No significant differences were detected between the latter two groups. 

Credit: Radiological Society of North America 

Brain iron levels offer a potential biomarker in the diagnosis of attention deficit hyperactivity disorder (ADHD) and may help physicians and parents make better informed treatment decisions, according to new research published online in the journal Radiology.

ADHD is a common disorder in children and adolescents that can continue into adulthood. Symptoms include hyperactivity and difficulty staying focused, paying attention and controlling behavior. The American Psychiatric Association reports that ADHD affects 3 to 7 percent of school-age children.

Psychostimulant medications such as Ritalin are among the drugs commonly used to reduce ADHD symptoms.

Psychostimulants affect levels of dopamine, a neurotransmitter in the brain associated with addiction.

"Much debate and concern has emerged regarding the continual rise of ADHD diagnosis in the U.S. given that two-thirds of those diagnosed receive psychostimulant medications," said Vitria Adisetiyo, Ph.D., postdoctoral research fellow at the Medical University of South Carolina in Charleston, S.C.

"We wanted to see if we could identify brain iron as a potential noninvasive biomarker for medication-naïve ADHD to prevent misdiagnosis."

For the study, the research team measured brain iron levels in 22 children and adolescents with ADHD, 12 of whom had never been on medication for their condition (medication naïve), and 27 healthy control children and adolescents using a magnetic resonance imaging (MRI) technique called magnetic field correlation imaging.


The technique was introduced in 2006 by study co-authors and faculty members Joseph A. Helpern, Ph.D., and Jens H. Jensen, Ph.D. No contrast agents were used, and blood iron levels in the body were measured using a blood draw.

The results showed that the 12 ADHD medication-naïve patients had significantly lower brain iron levels than the 10 ADHD patients who had been on psychostimulant medication and the 27 children and adolescents in the control group.

In contrast, ADHD patients with a history of psychostimulant medication treatment had brain iron levels comparable to controls, suggesting that brain iron may increase to normal levels with psychostimulant treatment.

"Our research suggests that iron absorption into the brain may be abnormal in ADHD given that atypical brain iron levels are found even when blood iron levels in the body are normal," Dr. Adisetiyo said.

"We found no differences in blood iron measures between controls, medication-naïve ADHD patients or pscyhostimulant-medicated ADHD patients."

If the results can be replicated in larger studies, magnetic field correlation might have a future role in determining which patients would benefit from psychostimulants—an important consideration because the drugs can become addictive if taken inappropriately and lead to abuse of other drugs like cocaine.

"We want the public to know that progress is being made in identifying potential noninvasive biological biomarkers of ADHD which may help to prevent misdiagnosis," Dr. Adisetiyo said.

"We are currently testing our findings in a larger cohort to confirm that measuring brain iron levels in ADHD is indeed a reliable and clinically feasible biomarker."

More information: "Multimodal MR Imaging of Brain Iron in Attention Deficit Hyperactivity Disorder: A Non-invasive Biomarker that Responds to Psychostimulant Treatment?" Radiology, 2014.

Tuesday, June 3, 2014

Children with autism have elevated levels of steroid hormones in the womb

Scientists from the University of Cambridge and the Statens Serum Institute in Copenhagen, Denmark have discovered that children who later develop autism are exposed to elevated levels of steroid hormones (for example testosterone, progesterone and cortisol) in the womb.

The finding may help explain why autism is more common in males than females, but should not be used to screen for the condition.

Funded by the Medical Research Council (MRC), the results are published today in the journal Molecular Psychiatry.

The team, led by Professor Simon Baron-Cohen and Dr Michael Lombardo in Cambridge and Professor Bent Nørgaard-Pedersen in Denmark, utilized approximately 19,500 amniotic fluid samples stored in a Danish biobank from individuals born between 1993-1999.

Amniotic fluid surrounds the baby in the womb during pregnancy and is collected when some women choose to have an amniocentesis around 15-16 weeks of pregnancy.

This coincides with a critical period for early brain development and sexual differentiation, and thus allows scientists access into this important window in fetal development.

The researchers identified amniotic fluid samples from 128 males later diagnosed with an autism spectrum condition and matched these up with information from a central register of all psychiatric diagnoses in Denmark.

Within the amniotic fluid the researchers looked at 4 key 'sex steroid' hormones that are each synthesized, step-by-step from the preceding one, in the 'Δ4 sex steroid' pathway: progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone.

They also tested the steroid hormone cortisol that lies outside this pathway. The researchers found that levels of all steroid hormones were highly associated with each other and most importantly, that the autism group on average had higher levels of all steroid hormones, compared to a typically developing male comparison group.

Professor Baron-Cohen said: "This is one of the earliest non-genetic biomarkers that has been identified in children who go on to develop autism."

"We previously knew that elevated prenatal testosterone is associated with slower social and language development, better attention to detail, and more autistic traits."

"Now, for the first time, we have also shown that these steroid hormones are elevated in children clinically diagnosed with autism."

"Because some of these hormones are produced in much higher quantities in males than in females, this may help us explain why autism is more common in males."

He added: "These new results are particularly striking because they are found across all the subgroups on the autism spectrum, for the first time uniting those with Asperger Syndrome, classic autism, or Pervasive Developmental Disorder Not-Otherwise-Specified. We now want to test if the same finding is found in females with autism."

Dr Michael Lombardo said: "This result potentially has very important implications about the early biological mechanisms that alter brain development in autism and also pinpoints an important window in fetal development when such mechanisms exert their effects."

Steroid hormones are particularly important because they exert influence on the process of how instructions in the genetic code are translated into building proteins.

The researchers believe that altering this process during periods when the building blocks for the brain are being laid down may be particularly important in explaining how genetic risk factors for autism get expressed.

Dr Lombardo adds: "Our discovery here meshes nicely with other recent findings that highlight the prenatal period around 15 weeks gestation as a key period when important genetic risk mechanisms for autism are working together to be expressed in the developing brain."

Professor Baron-Cohen said: "These results should not be taken as a reason to jump to steroid hormone blockers as a treatment as this could have unwanted side effects and may have little to no effect in changing the potentially permanent effects that fetal steroid hormones exert during the early foundational stages of brain development."

He cautioned further: "Nor should these results be taken as a promising prenatal screening test. There is considerable overlap between the groups and our findings showed differences found at an average group level, rather than at the level of accurately predicting diagnosis for individuals."

"The value of the new results lies in identifying key biological mechanisms during fetal development that could play important roles in atypical brain development in autism."

Sunday, May 4, 2014

Bob Hopkins: Played an early role in helping adults learn to read

British actor Bob Hoskins, who recently died aged 71, was the star of several big-screen blockbusters movies as a mobster or as the sidekick to Roger Rabbit but his early role in a BBC adult education series made a different kind of impact.

"On the move, on the move, we're on the move again," crooned 1970s cabaret-poppers The Dooleys over the opening credits.

There followed 10 minutes of clips and sketches aimed at helping adults overcome literacy problems. It was an unlikely setting from which to launch a Hollywood career.

But each episode of the 1976 BBC series On the Move featured a running storyline in which the late Bob Hoskins appeared as Alf Hunt, a furniture removal man who had difficulty reading and writing.

A proud but sympathetic character, Alf would open up to his friend Bert, played by Donald Gee, about his fears and frustrations.

His progress, as he sought help, attracted a huge following well beyond the show's target audience.

Up to 17 million people watched the Sunday tea-time programme, according to George Auckland, who would subsequently take charge of the BBC's adult education programming.

It was Alf's human drama and, specifically, Hoskins's captivating performance that drew them in, said Auckland.

A national campaign to tackle illiteracy was boosted by the series. On the Monday after each episode, says Auckland, "there would be queues around the block" at adult literacy centres.

"There's a strong argument that this makes Hoskins the best educator Britain has ever produced" but this is an exaggeration and Hopkins motive for joining the programme may have more to do with trying to get on the ladder to fame and fortune, which he eventually managed to do.

What we can say is that the broadcasting and media services can go a long way to normalising and helping to overcome the difficulties that some adults have when reading.

The media can also push forward willing celebrities who can captivate audiences and in doing so encourage the expansion and development of adult education in everyday life.

We are sadden by the death of Bob Hopkins as we are saddened by the passing of all men /women. We congratulate and celebrate his success in the film industry and we thank him for the part he played in helping adult education.

Friday, April 25, 2014

Autism Genome Project delivers genetic discovery

A new study from investigators with the Autism Genome Project (AGP), the world's largest research project on identifying genes associated with risk for autism, has found that the comprehensive use of copy number variant (CNV) genetic testing offers an important tool in individualized diagnosis and treatment of autism.

Funded primarily by Autism Speaks, the world's leading autism science and advocacy organization, the Autism Genome Project (AGPinvolved more than 50 research centers in 11 countries.

The report, published today in the American Journal of Human Genetics, delivers on the 10-year project's objective to provide practical methods for earlier diagnosis and personalized treatment of autism.

Rob Ring
"With the publication of this study, we should step back to recognize and celebrate the pioneering achievements of the AGP and what they have accomplished in helping to launch the field of genomic risk discovery in autism," says Autism Speaks Chief Science Officer Rob Ring.

"The AGP has generated information that holds the potential to guide medical care for certain individuals with autism today."

"They have demonstrated that science can work for families, and Autism Speaks is proud to have been a supporter of the work all along the way."

The study involved CNV testing of 2,446 families affected by autism and 4,768 individuals unaffected by neurologic or psychiatric disorders.

Overall, CNV s were significantly more common in the participating families affected by autism and, the CNV testing uncovered dozens of cases where autism-linked gene changes were associated with additional health risks warranting medical attention.

In nine of the families affected by autism, CNV s involved a gene that indicates elevated risk for seizures and epilepsy.

Stephen Scherer
"This result warrants an immediate referral to a neurologist," explains senior author Stephen Scherer of the Toronto's Hospital for Sick Children and the University of Toronto.

Similarly, CNV  testing indicated a high risk for Duchene muscular dystrophy in several of the autism families and identified syndromes associated with heart problems in others.

CNV s are genetic changes that involve duplication or deletion of entire segments of DNA.

They do not typically show up on standard genetic tests which search for "spelling mistakes" in the DNA letters that compose a gene.

Those standard tests identify a clear genetic autism link in only 15 to 20 percent of the cases.

"This report and its extensive supplements should become a new guidebook for medical geneticists working with families affected by autism," Dr. Scherer says.

In addition, the study added dozens of genes to the growing list of those that contribute to the development of autism.

Surprisingly, the autism genes identified through CNV testing had little overlap with those detected using standard exome gene sequencing, yet researchers say they affect the same brain pathways.

"These gene discoveries will help guide further research on autism subtypes and their treatment," Dr. Scherer says.

In response, the investigators urge medical geneticists to add CNV testing to the standard gene tests for autism and to consult medical recommendations for the many autism-linked syndromes that CNV testing can reveal.

CNV testing is currently available, though it's not typically part of standard genetic testing for autism.

Whole genome sequencing is the next step in genetic testing for Autism but is not yet widely available in ordinary medical settings.

Autism Speaks has taken a world-leadership position in in this direction with its Autism Ten Thousand Genomes (Aut10K) program.

More Information: "Convergence of Genes and Cellular Pathways Dysregulated in Autism Spectrum Disorders" American Journal of Human Genetics: ((2014), doi.org/10.1016/j.ajhg.2014.03.018

Thursday, April 24, 2014

Making your child into an Accomplished Liar

A primary rule for parents when dealing with lying is don't badger or corner children! Imagine you give a child the third degree about whether or not she has homework.

She denies it six times and finally, after your seventh question, she admits that, Yes, she has some.

What has happened?

By this time, of course, you are furious. More important, however, you also have given your child six times to practice lying!

You may think to yourself, "Sooner or later she'll realize she can't fool me and she'll give up." Wrong. Many children will continue to take the easy way out: they will simply attempt to avoid any confrontation with you and become better liars.

Either You Know the Truth or You Don’t
Look at it this way: you either know the truth or you don't. If you don't know what is going on, ask once and don't badger.

It's a good idea here not to ask "impulsively”.

Many kids simply respond back impulsively. They lie, but their real desire is just to end the conversation, get rid of you, and avoid trouble.

If you are going to ask, you might say something like, "I want you to tell me the story of what happened, but not right now. Think about it a while and we'll talk in fifteen minutes."

If she tells you the story and you find out later that the child lied, punish her for whatever the offense was as well as for the lie. No lectures or tantrums from you.

Deal with the problem and try to fix things, as best you can, so that lying does not seem necessary to the child.

If you do know what has happened, tell her what you know and deal with it. If she has done something wrong that you know about, simply punish her reasonably for that and end the conversation with, "I'm sure you'll do better next time."

Keep Your Perspective
Some parents still prefer to ask a child what happened, even when they already know what it was. This is OK if you do it right.

You should say something like, "I got a call from the school today about an incident at lunch. I'm going to ask you to tell me the story, but not right now. I want you to think about it for a while, and then when you're ready you can tell me, but remember I already pretty much know what happened."

Lying is not good, but it certainly isn't the end of the world either. It happens from time to time. It doesn't mean that your kids don't love you or that they are bound to grow up to become professional criminals.

However, over time, frequent emotional overreactions on your part, combined with badgering and cornering, can produce a very Accomplished Liar.

Monday, April 21, 2014

ADHD: Language problems common in children with ADHD

Children who have attention-deficit/hyperactivity disorder are nearly three times more likely to have language problems than kids without ADHD, according to new research.

And those language difficulties can have far-reaching academic consequences, the study found.

The study, published online April 21 in Pediatrics, looked at 6- to 8-year-olds with and without ADHD in Australia.

"We found that 40 percent of children in the ADHD group had language problems, compared to 17 percent of children in the 'control' group," said Emma Sciberras, a clinical psychologist and post-doctoral research fellow at the Murdoch Children's Research Institute in Victoria, Australia.

"Rates of language problems were similar in boys and girls with ADHD," she added.

Emma Sciberras
Children with ADHD commonly have trouble with school performance and social functioning.

The impact that language problems might have on these factors hasn't been well-studied, the study authors noted.

"The differences in academic functioning between children with ADHD and language problems, compared to those with ADHD alone, were quite large and clinically meaningful," said Sciberras.

Language problems refer to spoken language—both receptive and expressive language. Receptive language is the ability to listen and understand what's being said; expressive is the ability to speak and be understood.

In a separate study in the same issue of the journal, Sciberras and her colleagues looked at almost 400 children with ADHD, aged 5 to 13, and found almost two-thirds had one or more anxiety disorders.

When children with ADHD had two or more anxiety disorders—this was true for one-third of the kids—their quality of life, behavior and daily functioning suffered, the researchers said.

"It is very common for children with ADHD to experience additional difficulties," said Sciberras. "Both of these studies demonstrate that the additional difficulties that go along with ADHD, in this case anxiety and language problems, can make daily functioning even harder for children with ADHD."

The language study included 179 children diagnosed with ADHD and 212 without the attention disorder. Fewer than half of the children with ADHD were taking medications to help control their symptoms.

After adjusting for sociodemographic factors and other conditions, such as autism spectrum disorders, the researchers found that the risk of language problems was 2.8 times higher in children with ADHD.

When the researchers looked at how those language problems affected school work, they found lower math, reading and academic scores.

However, the researchers didn't find that language problems had an impact on social functioning.

"We were surprised that language problems were not associated with poorer social functioning for children with ADHD," Sciberras said.

"It could be that children with ADHD are already experiencing poorer social functioning due to other factors including their ADHD symptoms or other associated difficulties."

However, Sciberras cautioned that language troubles might become more problematic as these kids get older because social relationships get more complex with age.

One outside expert said the study is a good reminder for parents and physicians.

Bradley Berg
"If a child has ADHD and they're struggling in school, even though their ADHD symptoms are well-controlled, in addition to getting tested for learning disabilities, they should also be looked at for language difficulties as well. And that's not something we always think of," said Dr. Bradley Berg, medical director of McLane Children's Pediatrics at Baylor Scott & White Healthcare in Round Rock, Texas.

Whether speech-language interventions will help the youngsters with ADHD isn't clear, however.

Berg also pointed out that this issue is a "chicken-and-egg" problem.

He said "We don't know if these kids have;
  • a language disorder that's causing them to not understand what's going on at school 
      • and that's making them restless and fidgety because they're bored
  • Or do they have ADHD and that's causing difficulty understanding the language. 
  • Or is there something going on in an area of the brain that creates both of these problems?

It's possible that the findings from this Australian study might not translate to a U.S. population.

For one thing, medication trends might differ, Berg said. For children with ADHD who also suffer anxiety, Sciberras said medications might help, and a type of psychotherapy called cognitive behavioral therapy could also be useful.

The researchers are currently conducting a study to treat anxiety in children with ADHD.

"If parents are concerned that their child with ADHD has anxiety, language or any other additional difficulties that are not currently being managed, we encourage them to discuss their concerns with their child's treating clinician," she said.

Dyslexia : Perception Poster


Friday, April 18, 2014

Autism: Diagnosis and Treatment

In the US April is National Autism Awareness Month.

The Child Development Clinic at Children's Hospital of Richmond at VCU (CHoR) provides comprehensive assessment for pediatric patients with developmental delays or disabilities, including those with autism spectrum disorders.

The medical, psychological, social work and educational testing offered by the clinic leads to a diagnosis and recommendations to help patients and their health care providers with care planning, referrals, follow-up care coordination and treatments.

Pasquale Accardo
We sat down with Pasquale Accardo, M.D., professor and chief of the Division of Developmental Pediatrics at CHoR, to learn more about autism, including symptoms, diagnosis and treatment.

What is autism?

Autism is a neurodevelopmental disorder, this means that it is a chronic brain problem, a difficulty that the brain has with processing certain kinds of information.

In the case of autism, typically the greatest difficulty is dealing with social interaction.

What are the common signs and symptoms of autism?

Common signs of autism vary with age:

  • Young children often first present with language issues.
  • Preschool and school-age children often exhibit attention deficit hyperactivity disorder (ADHD) symptoms and other challenging behaviours.
  • Older children have significant socialization problems, repetitive and obsessive compulsive behaviours.

Symptoms of autism do change with time; certain delays are more common in younger children whereas socialization and processing problems are more common in older children and adults.

How is autism diagnosed?

Autism is diagnosed using a variety of approaches:


How is autism treated?

Autism is best treated with a variety of Early Intensive Behavioural Interventions (EIBI); speech language therapy and occupational therapy can also be used.

Applied Behaviour Analysis (ABA) is considered the standard for behavioral intervention, but most other effective behavioral programs are variants on ABA.

Tuesday, April 15, 2014

Autism: Parents advised to get a dog

Many families face the decision of whether to get a dog.

For families of children with autism, the decision can be even more challenging.

Now, a University of Missouri researcher has studied dog ownership decisions in families of children with autism and found, regardless of whether they owned dogs, the parents reported the benefits of dog ownership included companionship, stress relief and opportunities for their children to learn responsibility.

"Children with autism spectrum disorders often struggle with interacting with others, which can make it difficult for them to form friendships," said Gretchen Carlisle, a research fellow at the Research Center for Human-Animal Interaction (ReCHAI) in the MU College of Veterinary Medicine.

"Children with autism may especially benefit from interacting with dogs, which can provide unconditional, nonjudgmental love and companionship to the children."

Carlisle interviewed 70 parents of children with autism. Nearly two-thirds of the parents in the study owned dogs, and of those parents, 94 percent reported their children with autism were bonded to their dogs.

Even in families without dogs, 70 percent of parents said their children with autism liked dogs.

Many dog-owning parents said they specifically chose to get dogs because of the perceived benefits to their children with autism, Carlisle said.

"Dogs can help children with autism by acting as a social lubricant," Carlisle said. "For example, children with autism may find it difficult to interact with other neighbourhood children."

"If the children with autism invite their peers to play with their dogs, then the dogs can serve as bridges that help the children with autism communicate with their peers."

Parents of children with autism should consider their children's sensitivities carefully when choosing a dog in order to ensure a good match between pet and child, Carlisle said.

"Bringing a dog into any family is a big step, but for families of children with autism, getting a dog should be a decision that's taken very seriously," Carlisle said.

"If a child with autism is sensitive to loud noises, choosing a dog that is likely to bark will not provide the best match for the child and the family."

"If the child has touch sensitivities, perhaps a dog with a softer coat, such as a poodle, would be better than a dog with a wiry or rough coat, such as a terrier."

Carlisle recommends parents involve their children with autism when choosing a dog.

"Many children with autism know the qualities they want in a dog," Carlisle said. "If parents could involve their kids in choosing dogs for their families, it may be more likely the children will have positive experiences with the animals when they are brought home."

Although her study only addressed dog ownership among families affected by autism, Carlisle said dogs might not be the best pet for every child with autism.

"If you know one child with autism, you know one child with autism," Carlisle said. "Dogs may be best for some families, although other pets such as cats, horses or rabbits might be better suited to other children with autism and their particular sensitivities and interests."

"This research adds scientific credibility to the benefits of human-animal interaction," said Rebecca Johnson, a professor at the MU College of Veterinary Medicine, director of ReCHAI, and the Millsap Professor of Gerontological Nursing in the MU Sinclair School of Nursing.

"This research helps us understand the role of companion animals in improving the lives of children with autism and helps health professionals learn how to best guide families in choosing pets for their families."

The study, "Pet Dog Ownership Decisions for Parents of Children With Autism Spectrum Disorder," was published in the Journal of Pediatric Nursing earlier this year.